__init__.py 文件源码

def _warn_legacy_version(self):
        LV = packaging.version.LegacyVersion
        is_legacy = isinstance(self._parsed_version, LV)
        if not is_legacy:
            return

        # While an empty version is technically a legacy version and
        # is not a valid PEP 440 version, it's also unlikely to
        # actually come from someone and instead it is more likely that
        # it comes from setuptools attempting to parse a filename and
        # including it in the list. So for that we'll gate this warning
        # on if the version is anything at all or not.
        if not self.version:
            return

        tmpl = textwrap.dedent("""
            '{project_name} ({version})' is being parsed as a legacy,
            non PEP 440,
            version. You may find odd behavior and sort order.
            In particular it will be sorted as less than 0.0. It
            is recommended to migrate to PEP 440 compatible
            versions.
            """).strip().replace('\n', ' ')

        warnings.warn(tmpl.format(**vars(self)), PEP440Warning)